Chrome 150 kills uBlock Origin: Manifest V2 extensions disabled June 30

Google is weeks away from permanently disabling every Manifest V2 browser extension in Chrome. Chrome 150, scheduled for stable release on June 30, removes the ExtensionManifestV2Disabled flag — the last mechanism that allowed users and enterprise administrators to keep MV2 extensions running. Chrome 151, about four weeks later, strips the remaining MV2-related flags entirely. Google engineer Devlin Cronin confirmed the timeline in a Chromium code review commit that removes the flag infrastructure from Chrome’s codebase. Once the flags are gone, there is no workaround, no enterprise policy override, and no hidden setting to restore MV2 functionality.

The core technical change: webRequest → declarativeNetRequest

The Manifest V3 migration, first announced in 2019, replaces the webRequest API with the declarativeNetRequest API. The webRequest API allowed extensions to intercept and modify network traffic in real time — the foundation for dynamic content blocking. The new API requires extensions to submit static filtering rules in advance, which Chrome enforces natively. This means extensions cannot adapt to new threats, new advertising techniques, or new tracker domains without pushing an update through the Chrome Web Store review process.

uBlock Origin: 40 million users, no viable MV3 replacement

uBlock Origin, the most widely used content blocker on Chrome with more than 40 million users, relies on dynamic filtering to block ads, trackers, and malicious content on the fly. Its developer, Raymond Hill, has stated that a Manifest V3 version cannot replicate the full functionality of the original. A lighter version called uBlock Origin Lite exists for MV3, but it supports only a fraction of the filter lists and cannot perform the cosmetic filtering that makes the original effective against modern advertising techniques.

Google’s security argument — and its limits

Google’s security argument is not without merit. The webRequest API gives extensions deep access to every network request a browser makes, meaning a compromised or malicious extension can silently intercept passwords, redirect traffic, or inject code into any page. A recent case illustrates the risk: the popular “Save Image As Type” extension, with hundreds of thousands of users, was hijacked by a group calling itself Karma and silently modified to steal affiliate commissions from e-commerce transactions — a compromise that went undetected for months.

The declarativeNetRequest API prevents this class of attack by restricting extensions to predefined rule sets that Chrome enforces natively, rather than giving extensions arbitrary access to network traffic. The trade-off is that the rules are static. Extensions cannot adapt to new threats without pushing an update through the Chrome Web Store review process.

The business incentive question

Critics argue that the security case is inseparable from Google’s business incentives. Google generated an estimated $239.5 billion in advertising revenue in 2025 and is projected to be overtaken by Meta as the world’s largest digital advertising company in 2026. Content blockers directly reduce the number of ads users see. While Manifest V3 restrictions do not ban ad blocking entirely, they cap the number of filtering rules an extension can apply and eliminate the dynamic blocking that makes tools like uBlock Origin effective against rapidly evolving ad-delivery systems.

CISA recommends ad blockers — Chrome weakens them

The US Cybersecurity and Infrastructure Security Agency (CISA) has recommended the use of ad-blocking software as a defense against malvertising — the practice of distributing malware through legitimate advertising networks. A 2024 CISA guidance document specifically cited ad blockers as a layer of protection against drive-by downloads and malicious redirects served through programmatic ad exchanges. The Manifest V3 migration will weaken the most effective tool in that category on the browser used by roughly 65% of desktop internet users worldwide.

Alternatives: Firefox, Brave, or uBlock Origin Lite

Firefox, which is not built on Chromium and is not subject to Google’s extension framework, continues to support Manifest V2 and uBlock Origin in full. Mozilla has implemented its own version of Manifest V3 but has maintained backward compatibility with the webRequest API, allowing content blockers to function without restriction. Brave, which is Chromium-based, has built its own ad-blocking engine directly into the browser, bypassing the extension framework entirely.

For the estimated 40 million uBlock Origin users on Chrome, the practical options are limited:

  • Switch to Firefox or Brave for full-capability content blocking.
  • Install uBlock Origin Lite and accept reduced functionality.
  • Do nothing — Chrome 150 will silently disable the extension and display a notification that it is no longer supported.

The broader context: AI search and ad consolidation

The timing is notable: Google’s AI search overhaul, announced at I/O 2026, is already accelerating a traffic collapse for publishers who depend on search referrals. The simultaneous weakening of content blockers in Chrome means users will see more ads on the pages they do visit, while Google’s own AI-generated answers increasingly replace those pages altogether. The combined effect tightens Google’s grip on both the discovery and monetisation layers of the web.

What to do now

If you rely on uBlock Origin, you have until June 30 to find an alternative. Firefox and Brave are the only browsers that offer equivalent content-blocking capabilities. If you must stay on Chrome, switch to uBlock Origin Lite — but understand the limitations. The era of dynamic, real-time content blocking in Chrome is ending.